The six factory-spec bolts that hold the torque converter to the flexplate on GM automatics, in Grade 10.9 alloy steel so they clamp tight without stretching or backing out.
Pulling a 4L60E out of a Silverado, Tahoe or Camaro, or bolting a 4L80E behind an LS in a swap truck, ends the same way: the converter has to be fastened back to the flexplate. This is a set of six fresh M10-1.5 x 16mm flange bolts that replace GM part number 2307304, the converter bolt used across the 4L60E, 4L65E, 4L70E, 4L80E, 700-R4 and 200-4R. If you have a rattle from the bellhousing, a bolt that came out in the pan of the inspection cover, or you just do not want to reuse heat-cycled hardware on a fresh transmission, this is the part.
The torque converter rides on the transmission front pump at the back and is driven by the engine at the front. The only thing connecting the two is the flexplate and the bolts through its converter pads. Every bit of engine torque, every startup and every hard downshift passes through those few fasteners, so they need to hold clamp load without stretching. A typical 4L60E converter uses three lugs on a 10.75 or 11.06 inch circle, while ICT Billet notes that many heavy-duty 4L80E and TH400 converters use six bolts on an 11.5 inch circle. That means this kit covers one six-lug 4L80E converter, or two three-lug 4L60E jobs.
Length matters more than most people realize. GM's own Supermatic installation guide for the 4L65E and 4L70E warns that a bolt that is too long can push a dimple into the converter cover where the lockup clutch applies, and the lockup clutch then fails against the uneven surface. That is why a correct 16mm bolt, not whatever M10 bolt is in the coffee can, is worth the few dollars.
Not every bellhousing noise is the bolts. A cracked flexplate makes the same sound, and a converter that was never fully seated can destroy the pump. Our 4L60E common problems guide covers the pump and converter failures that show up after a careless install.
Remove the inspection cover and turn the engine over by hand with a socket on the crank bolt. Check each converter bolt with a wrench and look at the flexplate around every pad. If the plate is cracked or the holes are wallowed out, replace the flexplate with the bolts; the 6-bolt 4L80E flexplate is the match for a six-lug converter. If you are converting a 4L60E to a 4L80E, count the lugs on the converter you will actually run before ordering anything.
The listing covers the GM 4L60E, 4L65E, 4L70E, 4L80E, 700-R4, 200-4R and 3L80, plus the 4T60E and 4T65E front-drive units, all with the M10-1.5 x 16mm converter bolt. That includes 1993-2013 Silverado 1500, Sierra 1500, Tahoe, Suburban, Yukon, S10, Blazer, Camaro and Corvette with the 4L60E family. Aftermarket converters and flexplate spacers can change the thread engagement, so measure the thickness of your converter pad and flexplate before installing. If you are unsure, send us the year and VIN or the converter part number. More parts for these units are on our 4L60E parts page and the 4L80E parts page.
Rebuilding the unit while it is out? The 1995-2003 4L60E pump is the part a misaligned converter usually ruins.
| Quantity | 6 bolts |
| Fits | GM 4L60E, 4L65E, 4L70E, 4L80E, 700-R4, 200-4R, 3L80, 4T60E, 4T65E |
| OEM number | 2307304 |
| Thread | M10-1.5 x 16mm flange bolt |
| Grade | 10.9 alloy steel, ~1,040 MPa tensile |
| Finish | Galvanized, hex flange head |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
Most 4L60E converters bolt to the flexplate with three bolts. Many heavy-duty 4L80E converters use six. This set has six bolts, so it covers one six-lug converter or two three-lug installs.
GM's Supermatic 4L65E and 4L70E installation guide lists flywheel to converter at 37 ft-lb (50 N-m). Use the figure in your vehicle's service manual if it is different, tighten in a cross pattern and never use an air impact.
You can, but it is a poor gamble. They have been heat cycled and torqued before, and a bolt that loosens leads to a rattle, a damaged flexplate or a converter that walks on the pump. Fresh bolts are cheap insurance.
GM warns that a bolt that is too long can dimple the converter cover where the lockup clutch applies, which causes lockup clutch failure. These are the 16mm length GM uses for 2307304.
They fit factory-thickness pads and flexplates. Thicker aftermarket pads or a spacer can change thread engagement, so measure first or send us your converter details.
